§ A database is an organised collection of data which is stored in a computer in such a way that its contents can easily be accessed, managed, updated and queried by a computer program.
§ A database usually contains data related to one particular entity or enterprise.
§ For Example: A library database will contain data about all its books, its employees, its members and its various transactions etc.
§ A database is designed in such a way that its contents can be accessed, retrieved, updated, searched and queried upon by as many applications as possible.
§ This centrally located collection of data offers many advantages to an enterprise, about which we will learn a little later.
Advantages of using a database:
§ Facilitates Sharing of data: Multiple users can pick a same piece of data at the same time, from a centrally stored database, and use it for different purposes. It also allows a same piece of data to be shared by multiple applications at the same time.
§ Avoids Duplicate of data: As all the data in a database is stored at one place in a central location, there are hardly any chances that a data entry may get repeated or duplicated.
§ Greatly reduces Data Inconsistency: As data is stored at a single central location, there is no chance of errors which come via storage of data at different locations.
§ Makes Data Validation Possible: As data is stored in databases, we can validate and keep a check on the data that is being entered, updated or deleted. This substantially avoids unauthorised access to the data stored in a database.
§ Links can be established: With a common database, relations or links can be established between the same database components and with other application programs.
Various Database Objects:
§ The Database window shows many objects in the objects bar suc as Tables, Queries, Forms, and Reports etc.
§ We can add these objects to our database window for creating a database. The commonly used database objects are described below:
§ A Table is the database object that stores related data in the form of Records (rows) and Fields (columns).
§ It is the database object that gives out a selective output based on certain criteria or conditions.
§ It is the database object that gives out a user – friendly layout and format to work with the database objects like tables to view, edit, delete the records etc.
§ The database object that is used to present and analyse data in formatted output that can be printed out directly on paper.
Data Access Pages:
§ It is another database object that can be made available on the Intranet or Internet for Interactive purposes.
§ It helps to link the page with databases made in other sources.
§ For Example: SQL Server.